fix(rpc): avoid unecessarily cloning Tipset

src/cli/subcommands/chain_cmd.rs

@@ -7,6 +7,7 @@ use list::ChainListCommand;
 mod prune;
 use prune::ChainPruneCommands;
 
+use super::print_pretty_lotus_json;
 use crate::blocks::{Tipset, TipsetKey};
 use crate::lotus_json::HasLotusJson;
 use crate::message::ChainMessage;
@@ -15,8 +16,7 @@ use anyhow::{bail, ensure};
 use cid::Cid;
 use clap::Subcommand;
 use nunny::Vec as NonEmpty;
-
-use super::print_pretty_lotus_json;
+use std::sync::Arc;
 
 #[derive(Debug, Clone, clap::ValueEnum)]
 pub enum Format {
@@ -143,7 +143,7 @@ impl ChainCommands {
 async fn tipset_by_epoch_or_offset(
     client: &rpc::Client,
     epoch_or_offset: i64,
-) -> Result<Tipset, jsonrpsee::core::ClientError> {
+) -> Result<Arc<Tipset>, jsonrpsee::core::ClientError> {
     let current_head = ChainHead::call(client, ()).await?;
 
     let target_epoch = match epoch_or_offset.is_negative() {

src/cli/subcommands/f3_cmd.rs

@@ -6,7 +6,7 @@ mod tests;
 
 use std::{
     borrow::Cow,
-    sync::LazyLock,
+    sync::{Arc, LazyLock},
     time::{Duration, Instant},
 };
 
@@ -151,7 +151,7 @@ impl F3Commands {
 
                 async fn get_heads(
                     client: &rpc::Client,
-                ) -> anyhow::Result<(Tipset, FinalityCertificate)> {
+                ) -> anyhow::Result<(Arc<Tipset>, FinalityCertificate)> {
                     let cert_head = client.call(F3GetLatestCertificate::request(())?).await?;
                     let chain_head = client.call(ChainHead::request(())?).await?;
                     Ok((chain_head, cert_head))

src/lotus_json/arc.rs

@@ -0,0 +1,25 @@
+// Copyright 2019-2025 ChainSafe Systems
+// SPDX-License-Identifier: Apache-2.0, MIT
+
+use super::*;
+use std::sync::Arc;
+
+impl<T: HasLotusJson + Clone> HasLotusJson for Arc<T> {
+    type LotusJson = T::LotusJson;
+
+    #[cfg(test)]
+    fn snapshots() -> Vec<(serde_json::Value, Self)> {
+        T::snapshots()
+            .into_iter()
+            .map(|(k, v)| (k, Arc::new(v)))
+            .collect()
+    }
+
+    fn into_lotus_json(self) -> Self::LotusJson {
+        (*self).clone().into_lotus_json()
+    }
+
+    fn from_lotus_json(lotus_json: Self::LotusJson) -> Self {
+        Arc::new(T::from_lotus_json(lotus_json))
+    }
+}

src/lotus_json/mod.rs

@@ -220,6 +220,7 @@ decl_and_test!(
 // but you MUST document any tech debt - the reason WHY it cannot be tested above.
 mod actors;
 mod allocation;
+mod arc;
 mod beneficiary_term; // fil_actor_miner_state::v12::BeneficiaryTerm: !quickcheck::Arbitrary
 mod bit_field; //  fil_actors_shared::fvm_ipld_bitfield::BitField: !quickcheck::Arbitrary
 mod bytecode_hash;

src/rpc/methods/chain.rs

@@ -141,7 +141,7 @@ impl RpcMethod<0> for ChainGetFinalizedTipset {
     );
 
     type Params = ();
-    type Ok = Tipset;
+    type Ok = Arc<Tipset>;
 
     async fn handle(
         ctx: Ctx<impl Blockstore + Send + Sync + 'static>,
@@ -154,7 +154,7 @@ impl RpcMethod<0> for ChainGetFinalizedTipset {
         match get_f3_finality_tipset(&ctx, ec_finality_epoch).await {
             Ok(f3_tipset) => {
                 tracing::debug!("Using F3 finalized tipset at epoch {}", f3_tipset.epoch());
-                Ok((*f3_tipset).clone())
+                Ok(f3_tipset)
             }
             Err(_) => {
                 // fallback to ec finality
@@ -164,7 +164,7 @@ impl RpcMethod<0> for ChainGetFinalizedTipset {
                     head,
                     ResolveNullTipset::TakeOlder,
                 )?;
-                Ok((*ec_tipset).clone())
+                Ok(ec_tipset)
             }
         }
     }
@@ -867,7 +867,7 @@ impl RpcMethod<2> for ChainGetTipSetByHeight {
     const DESCRIPTION: Option<&'static str> = Some("Returns the tipset at the specified height.");
 
     type Params = (ChainEpoch, ApiTipsetKey);
-    type Ok = Tipset;
+    type Ok = Arc<Tipset>;
 
     async fn handle(
         ctx: Ctx<impl Blockstore>,
@@ -879,7 +879,7 @@ impl RpcMethod<2> for ChainGetTipSetByHeight {
         let tss = ctx
             .chain_index()
             .tipset_by_height(height, ts, ResolveNullTipset::TakeOlder)?;
-        Ok((*tss).clone())
+        Ok(tss)
     }
 }
 
@@ -896,7 +896,7 @@ impl RpcMethod<2> for ChainGetTipSetAfterHeight {
     );
 
     type Params = (ChainEpoch, ApiTipsetKey);
-    type Ok = Tipset;
+    type Ok = Arc<Tipset>;
 
     async fn handle(
         ctx: Ctx<impl Blockstore>,
@@ -908,7 +908,7 @@ impl RpcMethod<2> for ChainGetTipSetAfterHeight {
         let tss = ctx
             .chain_index()
             .tipset_by_height(height, ts, ResolveNullTipset::TakeNewer)?;
-        Ok((*tss).clone())
+        Ok(tss)
     }
 }
 
@@ -937,11 +937,11 @@ impl RpcMethod<0> for ChainHead {
     const DESCRIPTION: Option<&'static str> = Some("Returns the chain head (heaviest tipset).");
 
     type Params = ();
-    type Ok = Tipset;
+    type Ok = Arc<Tipset>;
 
     async fn handle(ctx: Ctx<impl Blockstore>, (): Self::Params) -> Result<Self::Ok, ServerError> {
         let heaviest = ctx.chain_store().heaviest_tipset();
-        Ok((*heaviest).clone())
+        Ok(heaviest)
     }
 }
 
@@ -974,7 +974,7 @@ impl RpcMethod<1> for ChainGetTipSet {
     const DESCRIPTION: Option<&'static str> = Some("Returns the tipset with the specified CID.");
 
     type Params = (ApiTipsetKey,);
-    type Ok = Tipset;
+    type Ok = Arc<Tipset>;
 
     async fn handle(
         ctx: Ctx<impl Blockstore>,
@@ -983,7 +983,7 @@ impl RpcMethod<1> for ChainGetTipSet {
         let ts = ctx
             .chain_store()
             .load_required_tipset_or_heaviest(&tipset_key)?;
-        Ok((*ts).clone())
+        Ok(ts)
     }
 }
 
@@ -996,7 +996,7 @@ impl RpcMethod<1> for ChainGetTipSetV2 {
     const DESCRIPTION: Option<&'static str> = Some("Returns the tipset with the specified CID.");
 
     type Params = (ApiTipsetKey,);
-    type Ok = Tipset;
+    type Ok = Arc<Tipset>;
 
     async fn handle(_: Ctx<impl Blockstore>, _: Self::Params) -> Result<Self::Ok, ServerError> {
         Err(ServerError::unsupported_method())
@@ -1098,10 +1098,7 @@ pub(crate) fn chain_notify<DB: Blockstore>(
     let current = data.chain_store().heaviest_tipset();
     let (change, tipset) = ("current".into(), current);
     sender
-        .send(vec![ApiHeadChange {
-            change,
-            tipset: tipset.as_ref().clone(),
-        }])
+        .send(vec![ApiHeadChange { change, tipset }])
         .expect("receiver is not dropped");
 
     let mut subscriber = data.chain_store().publisher().subscribe();
@@ -1115,13 +1112,7 @@ pub(crate) fn chain_notify<DB: Blockstore>(
                 HeadChange::Apply(ts) => ("apply".into(), ts),
             };
 
-            if sender
-                .send(vec![ApiHeadChange {
-                    change,
-                    tipset: tipset.as_ref().clone(),
-                }])
-                .is_err()
-            {
+            if sender.send(vec![ApiHeadChange { change, tipset }]).is_err() {
                 break;
             }
         }
@@ -1254,7 +1245,7 @@ pub struct ApiHeadChange {
     pub change: String,
     #[serde(rename = "Val", with = "crate::lotus_json")]
     #[schemars(with = "LotusJson<Tipset>")]
-    pub tipset: Tipset,
+    pub tipset: Arc<Tipset>,
 }
 lotus_json_with_self!(ApiHeadChange);